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powerpc: Remove more traces of bootmem
[linux/fpc-iii.git] / kernel / bpf / core.c
blobd6594e457a25af32e41a4b46a00a43ddf0a2c46b
1 /*
2 * Linux Socket Filter - Kernel level socket filtering
3 *
4 * Based on the design of the Berkeley Packet Filter. The new
5 * internal format has been designed by PLUMgrid:
6 *
7 * Copyright (c) 2011 - 2014 PLUMgrid, http://plumgrid.com
8 *
9 * Authors:
10 *
11 * Jay Schulist <jschlst@samba.org>
12 * Alexei Starovoitov <ast@plumgrid.com>
13 * Daniel Borkmann <dborkman@redhat.com>
14 *
15 * This program is free software; you can redistribute it and/or
16 * modify it under the terms of the GNU General Public License
17 * as published by the Free Software Foundation; either version
18 * 2 of the License, or (at your option) any later version.
19 *
20 * Andi Kleen - Fix a few bad bugs and races.
21 * Kris Katterjohn - Added many additional checks in bpf_check_classic()
22 */
23
24 #include <linux/filter.h>
25 #include <linux/skbuff.h>
26 #include <linux/vmalloc.h>
27 #include <linux/random.h>
28 #include <linux/moduleloader.h>
29 #include <asm/unaligned.h>
30 #include <linux/bpf.h>
31
32 /* Registers */
33 #define BPF_R0 regs[BPF_REG_0]
34 #define BPF_R1 regs[BPF_REG_1]
35 #define BPF_R2 regs[BPF_REG_2]
36 #define BPF_R3 regs[BPF_REG_3]
37 #define BPF_R4 regs[BPF_REG_4]
38 #define BPF_R5 regs[BPF_REG_5]
39 #define BPF_R6 regs[BPF_REG_6]
40 #define BPF_R7 regs[BPF_REG_7]
41 #define BPF_R8 regs[BPF_REG_8]
42 #define BPF_R9 regs[BPF_REG_9]
43 #define BPF_R10 regs[BPF_REG_10]
44
45 /* Named registers */
46 #define DST regs[insn->dst_reg]
47 #define SRC regs[insn->src_reg]
48 #define FP regs[BPF_REG_FP]
49 #define ARG1 regs[BPF_REG_ARG1]
50 #define CTX regs[BPF_REG_CTX]
51 #define IMM insn->imm
52
53 /* No hurry in this branch
54 *
55 * Exported for the bpf jit load helper.
56 */
57 void *bpf_internal_load_pointer_neg_helper(const struct sk_buff *skb, int k, unsigned int size)
58 {
59 u8 *ptr = NULL;
60
61 if (k >= SKF_NET_OFF)
62 ptr = skb_network_header(skb) + k - SKF_NET_OFF;
63 else if (k >= SKF_LL_OFF)
64 ptr = skb_mac_header(skb) + k - SKF_LL_OFF;
65 if (ptr >= skb->head && ptr + size <= skb_tail_pointer(skb))
66 return ptr;
67
68 return NULL;
69 }
70
71 struct bpf_prog *bpf_prog_alloc(unsigned int size, gfp_t gfp_extra_flags)
72 {
73 gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO |
74 gfp_extra_flags;
75 struct bpf_prog_aux *aux;
76 struct bpf_prog *fp;
77
78 size = round_up(size, PAGE_SIZE);
79 fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
80 if (fp == NULL)
81 return NULL;
82
83 aux = kzalloc(sizeof(*aux), GFP_KERNEL | gfp_extra_flags);
84 if (aux == NULL) {
85 vfree(fp);
86 return NULL;
87 }
88
89 fp->pages = size / PAGE_SIZE;
90 fp->aux = aux;
91
92 return fp;
93 }
94 EXPORT_SYMBOL_GPL(bpf_prog_alloc);
95
96 struct bpf_prog *bpf_prog_realloc(struct bpf_prog *fp_old, unsigned int size,
97 gfp_t gfp_extra_flags)
98 {
99 gfp_t gfp_flags = GFP_KERNEL | __GFP_HIGHMEM | __GFP_ZERO |
100 gfp_extra_flags;
101 struct bpf_prog *fp;
102
103 BUG_ON(fp_old == NULL);
104
105 size = round_up(size, PAGE_SIZE);
106 if (size <= fp_old->pages * PAGE_SIZE)
107 return fp_old;
108
109 fp = __vmalloc(size, gfp_flags, PAGE_KERNEL);
110 if (fp != NULL) {
111 memcpy(fp, fp_old, fp_old->pages * PAGE_SIZE);
112 fp->pages = size / PAGE_SIZE;
113
114 /* We keep fp->aux from fp_old around in the new
115 * reallocated structure.
116 */
117 fp_old->aux = NULL;
118 __bpf_prog_free(fp_old);
119 }
120
121 return fp;
122 }
123 EXPORT_SYMBOL_GPL(bpf_prog_realloc);
124
125 void __bpf_prog_free(struct bpf_prog *fp)
126 {
127 kfree(fp->aux);
128 vfree(fp);
129 }
130 EXPORT_SYMBOL_GPL(__bpf_prog_free);
131
132 #ifdef CONFIG_BPF_JIT
133 struct bpf_binary_header *
134 bpf_jit_binary_alloc(unsigned int proglen, u8 **image_ptr,
135 unsigned int alignment,
136 bpf_jit_fill_hole_t bpf_fill_ill_insns)
137 {
138 struct bpf_binary_header *hdr;
139 unsigned int size, hole, start;
140
141 /* Most of BPF filters are really small, but if some of them
142 * fill a page, allow at least 128 extra bytes to insert a
143 * random section of illegal instructions.
144 */
145 size = round_up(proglen + sizeof(*hdr) + 128, PAGE_SIZE);
146 hdr = module_alloc(size);
147 if (hdr == NULL)
148 return NULL;
149
150 /* Fill space with illegal/arch-dep instructions. */
151 bpf_fill_ill_insns(hdr, size);
152
153 hdr->pages = size / PAGE_SIZE;
154 hole = min_t(unsigned int, size - (proglen + sizeof(*hdr)),
155 PAGE_SIZE - sizeof(*hdr));
156 start = (prandom_u32() % hole) & ~(alignment - 1);
157
158 /* Leave a random number of instructions before BPF code. */
159 *image_ptr = &hdr->image[start];
160
161 return hdr;
162 }
163
164 void bpf_jit_binary_free(struct bpf_binary_header *hdr)
165 {
166 module_free(NULL, hdr);
167 }
168 #endif /* CONFIG_BPF_JIT */
169
170 /* Base function for offset calculation. Needs to go into .text section,
171 * therefore keeping it non-static as well; will also be used by JITs
172 * anyway later on, so do not let the compiler omit it.
173 */
174 noinline u64 __bpf_call_base(u64 r1, u64 r2, u64 r3, u64 r4, u64 r5)
175 {
176 return 0;
177 }
178
179 /**
180 * __bpf_prog_run - run eBPF program on a given context
181 * @ctx: is the data we are operating on
182 * @insn: is the array of eBPF instructions
183 *
184 * Decode and execute eBPF instructions.
185 */
186 static unsigned int __bpf_prog_run(void *ctx, const struct bpf_insn *insn)
187 {
188 u64 stack[MAX_BPF_STACK / sizeof(u64)];
189 u64 regs[MAX_BPF_REG], tmp;
190 static const void *jumptable[256] = {
191 [0 ... 255] = &&default_label,
192 /* Now overwrite non-defaults ... */
193 /* 32 bit ALU operations */
194 [BPF_ALU | BPF_ADD | BPF_X] = &&ALU_ADD_X,
195 [BPF_ALU | BPF_ADD | BPF_K] = &&ALU_ADD_K,
196 [BPF_ALU | BPF_SUB | BPF_X] = &&ALU_SUB_X,
197 [BPF_ALU | BPF_SUB | BPF_K] = &&ALU_SUB_K,
198 [BPF_ALU | BPF_AND | BPF_X] = &&ALU_AND_X,
199 [BPF_ALU | BPF_AND | BPF_K] = &&ALU_AND_K,
200 [BPF_ALU | BPF_OR | BPF_X] = &&ALU_OR_X,
201 [BPF_ALU | BPF_OR | BPF_K] = &&ALU_OR_K,
202 [BPF_ALU | BPF_LSH | BPF_X] = &&ALU_LSH_X,
203 [BPF_ALU | BPF_LSH | BPF_K] = &&ALU_LSH_K,
204 [BPF_ALU | BPF_RSH | BPF_X] = &&ALU_RSH_X,
205 [BPF_ALU | BPF_RSH | BPF_K] = &&ALU_RSH_K,
206 [BPF_ALU | BPF_XOR | BPF_X] = &&ALU_XOR_X,
207 [BPF_ALU | BPF_XOR | BPF_K] = &&ALU_XOR_K,
208 [BPF_ALU | BPF_MUL | BPF_X] = &&ALU_MUL_X,
209 [BPF_ALU | BPF_MUL | BPF_K] = &&ALU_MUL_K,
210 [BPF_ALU | BPF_MOV | BPF_X] = &&ALU_MOV_X,
211 [BPF_ALU | BPF_MOV | BPF_K] = &&ALU_MOV_K,
212 [BPF_ALU | BPF_DIV | BPF_X] = &&ALU_DIV_X,
213 [BPF_ALU | BPF_DIV | BPF_K] = &&ALU_DIV_K,
214 [BPF_ALU | BPF_MOD | BPF_X] = &&ALU_MOD_X,
215 [BPF_ALU | BPF_MOD | BPF_K] = &&ALU_MOD_K,
216 [BPF_ALU | BPF_NEG] = &&ALU_NEG,
217 [BPF_ALU | BPF_END | BPF_TO_BE] = &&ALU_END_TO_BE,
218 [BPF_ALU | BPF_END | BPF_TO_LE] = &&ALU_END_TO_LE,
219 /* 64 bit ALU operations */
220 [BPF_ALU64 | BPF_ADD | BPF_X] = &&ALU64_ADD_X,
221 [BPF_ALU64 | BPF_ADD | BPF_K] = &&ALU64_ADD_K,
222 [BPF_ALU64 | BPF_SUB | BPF_X] = &&ALU64_SUB_X,
223 [BPF_ALU64 | BPF_SUB | BPF_K] = &&ALU64_SUB_K,
224 [BPF_ALU64 | BPF_AND | BPF_X] = &&ALU64_AND_X,
225 [BPF_ALU64 | BPF_AND | BPF_K] = &&ALU64_AND_K,
226 [BPF_ALU64 | BPF_OR | BPF_X] = &&ALU64_OR_X,
227 [BPF_ALU64 | BPF_OR | BPF_K] = &&ALU64_OR_K,
228 [BPF_ALU64 | BPF_LSH | BPF_X] = &&ALU64_LSH_X,
229 [BPF_ALU64 | BPF_LSH | BPF_K] = &&ALU64_LSH_K,
230 [BPF_ALU64 | BPF_RSH | BPF_X] = &&ALU64_RSH_X,
231 [BPF_ALU64 | BPF_RSH | BPF_K] = &&ALU64_RSH_K,
232 [BPF_ALU64 | BPF_XOR | BPF_X] = &&ALU64_XOR_X,
233 [BPF_ALU64 | BPF_XOR | BPF_K] = &&ALU64_XOR_K,
234 [BPF_ALU64 | BPF_MUL | BPF_X] = &&ALU64_MUL_X,
235 [BPF_ALU64 | BPF_MUL | BPF_K] = &&ALU64_MUL_K,
236 [BPF_ALU64 | BPF_MOV | BPF_X] = &&ALU64_MOV_X,
237 [BPF_ALU64 | BPF_MOV | BPF_K] = &&ALU64_MOV_K,
238 [BPF_ALU64 | BPF_ARSH | BPF_X] = &&ALU64_ARSH_X,
239 [BPF_ALU64 | BPF_ARSH | BPF_K] = &&ALU64_ARSH_K,
240 [BPF_ALU64 | BPF_DIV | BPF_X] = &&ALU64_DIV_X,
241 [BPF_ALU64 | BPF_DIV | BPF_K] = &&ALU64_DIV_K,
242 [BPF_ALU64 | BPF_MOD | BPF_X] = &&ALU64_MOD_X,
243 [BPF_ALU64 | BPF_MOD | BPF_K] = &&ALU64_MOD_K,
244 [BPF_ALU64 | BPF_NEG] = &&ALU64_NEG,
245 /* Call instruction */
246 [BPF_JMP | BPF_CALL] = &&JMP_CALL,
247 /* Jumps */
248 [BPF_JMP | BPF_JA] = &&JMP_JA,
249 [BPF_JMP | BPF_JEQ | BPF_X] = &&JMP_JEQ_X,
250 [BPF_JMP | BPF_JEQ | BPF_K] = &&JMP_JEQ_K,
251 [BPF_JMP | BPF_JNE | BPF_X] = &&JMP_JNE_X,
252 [BPF_JMP | BPF_JNE | BPF_K] = &&JMP_JNE_K,
253 [BPF_JMP | BPF_JGT | BPF_X] = &&JMP_JGT_X,
254 [BPF_JMP | BPF_JGT | BPF_K] = &&JMP_JGT_K,
255 [BPF_JMP | BPF_JGE | BPF_X] = &&JMP_JGE_X,
256 [BPF_JMP | BPF_JGE | BPF_K] = &&JMP_JGE_K,
257 [BPF_JMP | BPF_JSGT | BPF_X] = &&JMP_JSGT_X,
258 [BPF_JMP | BPF_JSGT | BPF_K] = &&JMP_JSGT_K,
259 [BPF_JMP | BPF_JSGE | BPF_X] = &&JMP_JSGE_X,
260 [BPF_JMP | BPF_JSGE | BPF_K] = &&JMP_JSGE_K,
261 [BPF_JMP | BPF_JSET | BPF_X] = &&JMP_JSET_X,
262 [BPF_JMP | BPF_JSET | BPF_K] = &&JMP_JSET_K,
263 /* Program return */
264 [BPF_JMP | BPF_EXIT] = &&JMP_EXIT,
265 /* Store instructions */
266 [BPF_STX | BPF_MEM | BPF_B] = &&STX_MEM_B,
267 [BPF_STX | BPF_MEM | BPF_H] = &&STX_MEM_H,
268 [BPF_STX | BPF_MEM | BPF_W] = &&STX_MEM_W,
269 [BPF_STX | BPF_MEM | BPF_DW] = &&STX_MEM_DW,
270 [BPF_STX | BPF_XADD | BPF_W] = &&STX_XADD_W,
271 [BPF_STX | BPF_XADD | BPF_DW] = &&STX_XADD_DW,
272 [BPF_ST | BPF_MEM | BPF_B] = &&ST_MEM_B,
273 [BPF_ST | BPF_MEM | BPF_H] = &&ST_MEM_H,
274 [BPF_ST | BPF_MEM | BPF_W] = &&ST_MEM_W,
275 [BPF_ST | BPF_MEM | BPF_DW] = &&ST_MEM_DW,
276 /* Load instructions */
277 [BPF_LDX | BPF_MEM | BPF_B] = &&LDX_MEM_B,
278 [BPF_LDX | BPF_MEM | BPF_H] = &&LDX_MEM_H,
279 [BPF_LDX | BPF_MEM | BPF_W] = &&LDX_MEM_W,
280 [BPF_LDX | BPF_MEM | BPF_DW] = &&LDX_MEM_DW,
281 [BPF_LD | BPF_ABS | BPF_W] = &&LD_ABS_W,
282 [BPF_LD | BPF_ABS | BPF_H] = &&LD_ABS_H,
283 [BPF_LD | BPF_ABS | BPF_B] = &&LD_ABS_B,
284 [BPF_LD | BPF_IND | BPF_W] = &&LD_IND_W,
285 [BPF_LD | BPF_IND | BPF_H] = &&LD_IND_H,
286 [BPF_LD | BPF_IND | BPF_B] = &&LD_IND_B,
287 [BPF_LD | BPF_IMM | BPF_DW] = &&LD_IMM_DW,
288 };
289 void *ptr;
290 int off;
291
292 #define CONT ({ insn++; goto select_insn; })
293 #define CONT_JMP ({ insn++; goto select_insn; })
294
295 FP = (u64) (unsigned long) &stack[ARRAY_SIZE(stack)];
296 ARG1 = (u64) (unsigned long) ctx;
297
298 /* Registers used in classic BPF programs need to be reset first. */
299 regs[BPF_REG_A] = 0;
300 regs[BPF_REG_X] = 0;
301
302 select_insn:
303 goto *jumptable[insn->code];
304
305 /* ALU */
306 #define ALU(OPCODE, OP) \
307 ALU64_##OPCODE##_X: \
308 DST = DST OP SRC; \
309 CONT; \
310 ALU_##OPCODE##_X: \
311 DST = (u32) DST OP (u32) SRC; \
312 CONT; \
313 ALU64_##OPCODE##_K: \
314 DST = DST OP IMM; \
315 CONT; \
316 ALU_##OPCODE##_K: \
317 DST = (u32) DST OP (u32) IMM; \
318 CONT;
319
320 ALU(ADD, +)
321 ALU(SUB, -)
322 ALU(AND, &)
323 ALU(OR, |)
324 ALU(LSH, <<)
325 ALU(RSH, >>)
326 ALU(XOR, ^)
327 ALU(MUL, *)
328 #undef ALU
329 ALU_NEG:
330 DST = (u32) -DST;
331 CONT;
332 ALU64_NEG:
333 DST = -DST;
334 CONT;
335 ALU_MOV_X:
336 DST = (u32) SRC;
337 CONT;
338 ALU_MOV_K:
339 DST = (u32) IMM;
340 CONT;
341 ALU64_MOV_X:
342 DST = SRC;
343 CONT;
344 ALU64_MOV_K:
345 DST = IMM;
346 CONT;
347 LD_IMM_DW:
348 DST = (u64) (u32) insn[0].imm | ((u64) (u32) insn[1].imm) << 32;
349 insn++;
350 CONT;
351 ALU64_ARSH_X:
352 (*(s64 *) &DST) >>= SRC;
353 CONT;
354 ALU64_ARSH_K:
355 (*(s64 *) &DST) >>= IMM;
356 CONT;
357 ALU64_MOD_X:
358 if (unlikely(SRC == 0))
359 return 0;
360 tmp = DST;
361 DST = do_div(tmp, SRC);
362 CONT;
363 ALU_MOD_X:
364 if (unlikely(SRC == 0))
365 return 0;
366 tmp = (u32) DST;
367 DST = do_div(tmp, (u32) SRC);
368 CONT;
369 ALU64_MOD_K:
370 tmp = DST;
371 DST = do_div(tmp, IMM);
372 CONT;
373 ALU_MOD_K:
374 tmp = (u32) DST;
375 DST = do_div(tmp, (u32) IMM);
376 CONT;
377 ALU64_DIV_X:
378 if (unlikely(SRC == 0))
379 return 0;
380 do_div(DST, SRC);
381 CONT;
382 ALU_DIV_X:
383 if (unlikely(SRC == 0))
384 return 0;
385 tmp = (u32) DST;
386 do_div(tmp, (u32) SRC);
387 DST = (u32) tmp;
388 CONT;
389 ALU64_DIV_K:
390 do_div(DST, IMM);
391 CONT;
392 ALU_DIV_K:
393 tmp = (u32) DST;
394 do_div(tmp, (u32) IMM);
395 DST = (u32) tmp;
396 CONT;
397 ALU_END_TO_BE:
398 switch (IMM) {
399 case 16:
400 DST = (__force u16) cpu_to_be16(DST);
401 break;
402 case 32:
403 DST = (__force u32) cpu_to_be32(DST);
404 break;
405 case 64:
406 DST = (__force u64) cpu_to_be64(DST);
407 break;
408 }
409 CONT;
410 ALU_END_TO_LE:
411 switch (IMM) {
412 case 16:
413 DST = (__force u16) cpu_to_le16(DST);
414 break;
415 case 32:
416 DST = (__force u32) cpu_to_le32(DST);
417 break;
418 case 64:
419 DST = (__force u64) cpu_to_le64(DST);
420 break;
421 }
422 CONT;
423
424 /* CALL */
425 JMP_CALL:
426 /* Function call scratches BPF_R1-BPF_R5 registers,
427 * preserves BPF_R6-BPF_R9, and stores return value
428 * into BPF_R0.
429 */
430 BPF_R0 = (__bpf_call_base + insn->imm)(BPF_R1, BPF_R2, BPF_R3,
431 BPF_R4, BPF_R5);
432 CONT;
433
434 /* JMP */
435 JMP_JA:
436 insn += insn->off;
437 CONT;
438 JMP_JEQ_X:
439 if (DST == SRC) {
440 insn += insn->off;
441 CONT_JMP;
442 }
443 CONT;
444 JMP_JEQ_K:
445 if (DST == IMM) {
446 insn += insn->off;
447 CONT_JMP;
448 }
449 CONT;
450 JMP_JNE_X:
451 if (DST != SRC) {
452 insn += insn->off;
453 CONT_JMP;
454 }
455 CONT;
456 JMP_JNE_K:
457 if (DST != IMM) {
458 insn += insn->off;
459 CONT_JMP;
460 }
461 CONT;
462 JMP_JGT_X:
463 if (DST > SRC) {
464 insn += insn->off;
465 CONT_JMP;
466 }
467 CONT;
468 JMP_JGT_K:
469 if (DST > IMM) {
470 insn += insn->off;
471 CONT_JMP;
472 }
473 CONT;
474 JMP_JGE_X:
475 if (DST >= SRC) {
476 insn += insn->off;
477 CONT_JMP;
478 }
479 CONT;
480 JMP_JGE_K:
481 if (DST >= IMM) {
482 insn += insn->off;
483 CONT_JMP;
484 }
485 CONT;
486 JMP_JSGT_X:
487 if (((s64) DST) > ((s64) SRC)) {
488 insn += insn->off;
489 CONT_JMP;
490 }
491 CONT;
492 JMP_JSGT_K:
493 if (((s64) DST) > ((s64) IMM)) {
494 insn += insn->off;
495 CONT_JMP;
496 }
497 CONT;
498 JMP_JSGE_X:
499 if (((s64) DST) >= ((s64) SRC)) {
500 insn += insn->off;
501 CONT_JMP;
502 }
503 CONT;
504 JMP_JSGE_K:
505 if (((s64) DST) >= ((s64) IMM)) {
506 insn += insn->off;
507 CONT_JMP;
508 }
509 CONT;
510 JMP_JSET_X:
511 if (DST & SRC) {
512 insn += insn->off;
513 CONT_JMP;
514 }
515 CONT;
516 JMP_JSET_K:
517 if (DST & IMM) {
518 insn += insn->off;
519 CONT_JMP;
520 }
521 CONT;
522 JMP_EXIT:
523 return BPF_R0;
524
525 /* STX and ST and LDX*/
526 #define LDST(SIZEOP, SIZE) \
527 STX_MEM_##SIZEOP: \
528 *(SIZE *)(unsigned long) (DST + insn->off) = SRC; \
529 CONT; \
530 ST_MEM_##SIZEOP: \
531 *(SIZE *)(unsigned long) (DST + insn->off) = IMM; \
532 CONT; \
533 LDX_MEM_##SIZEOP: \
534 DST = *(SIZE *)(unsigned long) (SRC + insn->off); \
535 CONT;
536
537 LDST(B, u8)
538 LDST(H, u16)
539 LDST(W, u32)
540 LDST(DW, u64)
541 #undef LDST
542 STX_XADD_W: /* lock xadd *(u32 *)(dst_reg + off16) += src_reg */
543 atomic_add((u32) SRC, (atomic_t *)(unsigned long)
544 (DST + insn->off));
545 CONT;
546 STX_XADD_DW: /* lock xadd *(u64 *)(dst_reg + off16) += src_reg */
547 atomic64_add((u64) SRC, (atomic64_t *)(unsigned long)
548 (DST + insn->off));
549 CONT;
550 LD_ABS_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + imm32)) */
551 off = IMM;
552 load_word:
553 /* BPF_LD + BPD_ABS and BPF_LD + BPF_IND insns are
554 * only appearing in the programs where ctx ==
555 * skb. All programs keep 'ctx' in regs[BPF_REG_CTX]
556 * == BPF_R6, bpf_convert_filter() saves it in BPF_R6,
557 * internal BPF verifier will check that BPF_R6 ==
558 * ctx.
559 *
560 * BPF_ABS and BPF_IND are wrappers of function calls,
561 * so they scratch BPF_R1-BPF_R5 registers, preserve
562 * BPF_R6-BPF_R9, and store return value into BPF_R0.
563 *
564 * Implicit input:
565 * ctx == skb == BPF_R6 == CTX
566 *
567 * Explicit input:
568 * SRC == any register
569 * IMM == 32-bit immediate
570 *
571 * Output:
572 * BPF_R0 - 8/16/32-bit skb data converted to cpu endianness
573 */
574
575 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 4, &tmp);
576 if (likely(ptr != NULL)) {
577 BPF_R0 = get_unaligned_be32(ptr);
578 CONT;
579 }
580
581 return 0;
582 LD_ABS_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + imm32)) */
583 off = IMM;
584 load_half:
585 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 2, &tmp);
586 if (likely(ptr != NULL)) {
587 BPF_R0 = get_unaligned_be16(ptr);
588 CONT;
589 }
590
591 return 0;
592 LD_ABS_B: /* BPF_R0 = *(u8 *) (skb->data + imm32) */
593 off = IMM;
594 load_byte:
595 ptr = bpf_load_pointer((struct sk_buff *) (unsigned long) CTX, off, 1, &tmp);
596 if (likely(ptr != NULL)) {
597 BPF_R0 = *(u8 *)ptr;
598 CONT;
599 }
600
601 return 0;
602 LD_IND_W: /* BPF_R0 = ntohl(*(u32 *) (skb->data + src_reg + imm32)) */
603 off = IMM + SRC;
604 goto load_word;
605 LD_IND_H: /* BPF_R0 = ntohs(*(u16 *) (skb->data + src_reg + imm32)) */
606 off = IMM + SRC;
607 goto load_half;
608 LD_IND_B: /* BPF_R0 = *(u8 *) (skb->data + src_reg + imm32) */
609 off = IMM + SRC;
610 goto load_byte;
611
612 default_label:
613 /* If we ever reach this, we have a bug somewhere. */
614 WARN_RATELIMIT(1, "unknown opcode %02x\n", insn->code);
615 return 0;
616 }
617
618 void __weak bpf_int_jit_compile(struct bpf_prog *prog)
619 {
620 }
621
622 /**
623 * bpf_prog_select_runtime - select execution runtime for BPF program
624 * @fp: bpf_prog populated with internal BPF program
625 *
626 * try to JIT internal BPF program, if JIT is not available select interpreter
627 * BPF program will be executed via BPF_PROG_RUN() macro
628 */
629 void bpf_prog_select_runtime(struct bpf_prog *fp)
630 {
631 fp->bpf_func = (void *) __bpf_prog_run;
632
633 /* Probe if internal BPF can be JITed */
634 bpf_int_jit_compile(fp);
635 /* Lock whole bpf_prog as read-only */
636 bpf_prog_lock_ro(fp);
637 }
638 EXPORT_SYMBOL_GPL(bpf_prog_select_runtime);
639
640 static void bpf_prog_free_deferred(struct work_struct *work)
641 {
642 struct bpf_prog_aux *aux;
643
644 aux = container_of(work, struct bpf_prog_aux, work);
645 bpf_jit_free(aux->prog);
646 }
647
648 /* Free internal BPF program */
649 void bpf_prog_free(struct bpf_prog *fp)
650 {
651 struct bpf_prog_aux *aux = fp->aux;
652
653 INIT_WORK(&aux->work, bpf_prog_free_deferred);
654 aux->prog = fp;
655 schedule_work(&aux->work);
656 }
657 EXPORT_SYMBOL_GPL(bpf_prog_free);
658
659 /* To execute LD_ABS/LD_IND instructions __bpf_prog_run() may call
660 * skb_copy_bits(), so provide a weak definition of it for NET-less config.
661 */
662 int __weak skb_copy_bits(const struct sk_buff *skb, int offset, void *to,
663 int len)
664 {
665 return -EFAULT;
666 }
Linux with added FPC-III support